UK
Mobile phone history

With
the UK introduction of 3G third generation cellular mobile phone services,
you could be forgiven for thinking that the '1G' analogue cell phone marked
the beginning of the story but in fact cellular technology was pre-dated
by another four generations...

System
1

The very
first public mobile telephone service in the UK was made available in
1959. It was of limited capacity and provided coverage in the South Lancashire
area.

It was not until 1965 that service was made available in London. The launch
coincided with the opening of the Post Office Tower, which was the location
for the base station transmitters covering the central London area. The
launch of system 2 saw the beginning of the ever increasing rise in popularity
of the mobile phone.

System
2

9 Channel Radiophone

By the early 1970's the state of the art was the Nine
Channel Radiophone. There were only three authorised suppliers of equipment,
Storno, Pye and Marconi.

The installation typically consisted of a control head, handset and loudspeaker
fitted in the front of the vehicle, connected to a transceiver unit usually
mounted in the boot connected to a whip antenna. Storno also produced
a transportable battery operated version for pedestrian use.

Coverage and capacity

The
coverage maps show service
was gradually extended to cover London, Birmingham, Bristol, Manchester,
Newcastle and parts of Scotland. Although refered to as the nine channel
radiophone, in fact the equipment had ten channels, nine manually selectable
for initiating calls, and 1 for incoming call signalling (automatically
selected when the handset was resting in it's cradle). Each subscriber
was allocated a five digit number. London numbers always started with
a 1, Provincial numbers varied by area. This also affected which group
of nine channels were supplied (i.e. not all users had the same nine channels,
six different channel groups were available).

Operation

A
mobile call was initiated by lifting the handset, manually selecting a
free channel and pressing the call button (specific channels were used
in specific areas, busy channels were indicated by an engaged light).
A ringing tone would be heard until an operator answered. The subscriber
would give their five digit mobile number followed by the number they
wished to call. The operator would make the connection and the call would
continue until the mobile replaced the handset in the cradle which would
clear down the call. It should be noted that from the mobile perspective
the conversation was one way at a time, the transmit button on the handset
had to be pressed to talk, released to listen.

To
call a mobile from a fixed telephone it was necessary to call the radiophone
operator by dialling 140 (in London) and requesting the 5 digit number
of the mobile you wished to be connected to. The operator would key in
the number which would be transmitted using a 5 tone sequence to all mobiles
on the calling channel. The mobile, if available would respond with a
single tone to acknowledge the call. The mobile would be alerted and could
respond to the call using the same procedure as for a mobile initiated
call, with the small difference that the tone sent when the mobile initiated
the call would be different, this would give an indication at the exchange
as to whether it was a mobile initiated call or a response to an incoming
call.

Security

You
may wonder what was to stop somebody 'pirating' another number when initiating
a call. The answer is not much but remember these were simpler times!
As for the possibility of monitoring other people's conversations, the
control logic tried to prevent this but some users discovered you could
lift the handset, select an engaged channel, then remove the antenna,
press the call button then replace the antenna. You could then hear the
conversation on that channel.

Alternatives

The
General Post Office - GPO had an almost total monopoly on telecommunications
in the UK at this time and the regulations concerning interconnection
between other radio systems and the public telephone network restricted
operation to emergency use only. The only 'competing' service was exclusively
for marine use. The other alternative was to use message handling services
provided by companies such as AirCall, ReadyCall, Selective Audio Messaging
and Securicor.

System
3

55
Channel Automatic System

The
system was further developed with the arrival in 1977 of the Storno Fifty-Five
Channel Automatic Radiophone. This had the advantages that an idle channel
was found and called automatically, just by lifting the handset. Also
because the unit could automatically scan all the available channels there
was a much better chance of finding a free channel quickly.

System three was an 'overlay' system which used the same frequencies and
calling channel as the 9 Channel system. Idle channels were identified
by a marker signal consisting of a two-tone combination. Different combinations
were used in different parts of the country. The mobile had a six button
area selector marked A E I O U and X, although only the first three were
physically enabled. London area used button A which had a marker tone
combination of 2000 Hz and 2200 Hz. When the subscriber lifted the handset
from it's rest the mobile would scan all the channels searching for the
marker signal and the control logic could also sample the strength
of the received signal to ensure a good quality connection. Once a good
signal had been detected the mobile sent the call tone automatically and
the ringing tone would be heard until the operator answered. Apart from
the automatic search, the operation was similar to the 9 channel equipment

System
4

Automatic Direct
Dial System

All
the previous systems relied on an operator assisted connection to the
subscriber but 1983 brought the UK's first direct dial carphone. The National
Automatic Radiophone Service (also known as Public Radio Telephone System
Four or PRT4) used full duplex two-way transmission, removing the need
for a press to speak button. It also provided a service with greater geographical
coverage.

This final incarnation before the advent of cellular systems also used
the same frequency range as the earlier 55 Channel system and in order
to provide more capacity it was necessary to modify all the existing 9
and 55 channel equipment from 25 kHz to 12.5 kHz channel spacing. This
allowed the new system to interleave with the existing system without
causing interference and then to gradually increase capacity while phasing
out the old manual system. The system had 95 channels and the system
coverage area increased to provide service in most of the
major population centres.

The Stornomatic 900 installation was similar to the previous models with
a control box usually fitted under the dashboard and the transceiver unit
in the boot. The control box had a numeric keypad and display and facilities
included some now familiar user features such as number memory and security
lock codes.

To dial a mobile
number it was necessary to dial a regional area code related to the location
of the mobile, followed by the six digit mobile number. To call mobile 215063
in the London area one would dial 0034 215063.